Dislocations were first discovered by Volterra [22],
Weingarten [23], Somigliana [24] in the context of
continuum mechanics. They developed the elastic properties of
"macro"-dislocations in isotropic continua. It was only
some 30 years later that the subject gained added
importance through studies of discrete crystal lattices.
Dislocations ceased to be mathematical curiosity when Orowan
[25], Polanyi [26] and Taylor [27] predicted the existence
of crystal imperfections that configurationally
corresponded to dislocations. In 1934 they introduced the concept
of an edge dislocation, a line-shaped crystal defect, into
solid state physics. Five years later Burgers [28]
discovered the second fundamental type of dislocations, the
screw dislocations and developed what could be called the
elastostatics of singular dislocations, both for isotropic
and anisotropic media [29].